This invention is generally directed to photoconductive imaging members, and more specifically to imaging members with polyphosphazene, including polyorganophosphazene hole blocking layers. The present invention in one embodiment is directed to layered imaging members comprised of a photogenerating layer, a charge transport layer, and a charge blocking layer comprised of polyphosphazenes. In a specific embodiment, the present invention relates to layered imaging members comprised of a supporting substrate, a hole blocking layer comprised of polyphosphazenes, a photogenerating layer and a hole transport layer, especially an aryl amine, wherein the amine molecules are dispersed in an inactive resin binder. Further, in another embodiment of the present invention the imaging member is comprised of a supporting substrate, a hole blocking layer comprised of polyphosphazenes, which polyphosphazenes also possess adhesive characteristics, thereby avoiding the need for a separate adhesive layer, such as a polyester, a photogenerating layer, and in contact therewith a charge transport layer. The charge, especially hole, transport layer can be located as the top layer of the imaging member, or it may be situated between the supporting substrate and the photogenerating layer. The aforementioned polyphosphazene hole blocking-adhesive material possesses a number of advantages including, but not limited to, for example, its adhesive characteristics, especially for seamless layered imaging members; the capability of the polyphosphazene to form smooth thin uniform films by, for example, solution coating as compared to known silane layers, which form in many instances undesirable islands, and nonuniform films; stable properties when dissolved in solvents; the polyphosphazene coating can be applied by spray, dipped, or web coating processes permitting more economical processes, and improved efficiency; resiliency characteristics compared to, for example, the brittle characteristics of organo silane layers which causes cracking; and the like. The imaging members of the present invention can be selected for a number of imaging and printing processes including electrophotographic imaging and printing processes for an extended number of imaging cycles, while substantially avoiding or minimizing undesirable separation of the layers, substantially avoiding or minimizing undesirable charge injection from the supporting substrate to the photogenerating and other layers of the imaging member, excellent adherence to the metal ground plane layer situated on the supporting substrate in some embodiments, superior and ease of coatability of the polyphosphazenes, adherence to a number of substrates such as conductive polymers, metals and the salts thereof such as copper iodide, organic ground planes, and the like, thus enabling seamless imaging members.
The formation and development of electrostatic latent images on the imaging surfaces of photoconductive materials by electrostatic means is well known. Numerous different photoconductive members for use in xerography are known such as selenium, alloys of selenium, layered imaging members comprised of aryl amine charge transport layers, reference U.S. Pat. No. 4,265,990, and imaging members with charge transport layers comprised of polysilylenes, reference U.S. Pat. No. 4,618,551. The disclosures of the aforementioned patents are totally incorporated herein by reference.
In a patentability search report, there were recited the following United States patents: U.S. Pat. No. 4,657,993 directed to polyphosphazene homopolymers and copolymers with hydroxylated or amino derivatives, for example, reference the Abstract of the Disclosure, which polyphosphazenes can be selected as photoconductor materials and can be used for the reproduction of images or for other uses, see column 1, line 55, to column 2, line 21; and primarily of background interest, U.S. Pat. No. 3,370,020 directed to phosphonitrilic polymer mixtures, reference the Abstract of the Disclosure; U.S. Pat. No. 3,515,688 directed to copolymers containing phosphonitrile elastomers, reference the Abstract of the Disclosure for example; U.S. Pat. No. 3,702,833 directed to curable fluorophosphene polymers, reference the Abstract of the Disclosure and column 1; and U.S. Pat. No. 3,856,712 directed to polyphosphazene copolymers, which are elastomers, reference the Abstract of the Disclosure and column 1. The disclosures of each of the aforementioned patents are totally incorporated herein by reference.
The following patent applications and U.S. patents which illustrate layered imaging members with adhesive and hole blocking layers in some instances are mentioned: (1) U.S. Pat. No. 4,818,650 describes layered imaging members with novel polymeric, hydroxy and alkoxy aryl amines, wherein m is a number of between about 4 and 1,000 reference for example claims 1 and 2; (2) U.S. Ser. No. 061,247 (now abandoned) and U.S. Pat. No. 4,871,634 illustrate imaging members with novel dihydroxy terminated aryl amine small molecules, reference claims 1 and 2 for example; (3) U.S. Pat. No. 4,806,444, the disclosure of which is totally incorporated herein by reference, describes layered imaging members with novel polycarbonate polymeric aryl amines, reference claims 1 and 2, for example; (4) U.S. Pat. No. 4,806,443, the disclosure of which is totally incorporated herein by reference, illustrates novel polycarbonate polymeric amines useful in layered imaging members, reference claims 1 and 2 for example; and (5) U.S. Pat. No. 4,801,517, the disclosure of which is totally incorporated herein by reference, which discloses imaging members with novel polycarbonate aryl amines, reference claims 1 and 2, for example.
In U.S. Pat. No. 4,869,988 and U.S. Pat. No. 4,946,754 entitled, respectively, PHOTOCONDUCTIVE IMAGING MEMBERS WITH N,N-BIS(BIARYLYL)ANILINE, OR TRIS(BIARYLYL)AMINE CHARGE TRANSPORTING COMPONENTS, and PHOTOCONDUCTIVE IMAGING MEMBERS WITH BIARYLYL DIARYLAMINE CHARGE TRANSPORTING COMPONENTS, the disclosures of which are totally incorporated herein by reference, there are described layered photoconductive imaging members with transport layers incorporating biarylyl diarylamines, N,N-bis(biarylyl)anilines, and tris(biarylyl)amines as charge transport compounds. In the abovementioned patents, there are disclosed improved layered photoconductive imaging members comprised of a supporting substrate, a photogenerating layer optionally dispersed in an inactive resinous binder, and in contact therewith a charge transport layer comprised of the abovementioned charge transport compounds, or mixtures thereof dispersed in resinous binders. These patent applications also disclose, for example, polyester adhesive and metal oxide or organo silane hole blocking layers.
Examples of specific hole transporting components disclosed in U.S. Pat. No. 4,869,988 include N,N-bis(4-biphenylyl)-3,5-dimethoxyaniline (Ia); N,N-bis(4-biphenylyl)-3,5-dimethylaniline (Ib); N,N-bis(4-methyl-4'-biphenylyl)-3-methoxyaniline (Ic); N,N-bis(4-methyl-4'-biphenylyl)-3-chloroaniline (Id); N,N-bis(4-methyl-4'-biphenylyl)-4-ethylaniline (Ie); N,N-bis(4-chloro-4'-biphenylyl)-3-methylaniline (If); N,N-bis(4-bromo-4'-biphenylyl)-3,5-dimethoxyaniline (Ig); 4-biphenylyl bis(4-ethoxycarbonyl-4'-biphenylyl)amine (IIa); 4-biphenylyl bis(4-acetoxymethyl-4'-biphenylyl)amine (IIb); 3-biphenylyl bis(4-methyl-4'-biphenylyl)amine (IIc); 4-ethoxycarbonyl-4'-biphenylyl bis(4-methyl-4'-biphenylyl)amine (IId); and the like.
Examples of specific hole transporting compounds disclosed in U.S. Pat. No. 4,946,754 include bis(p-tolyl)-4-biphenylylamine (IIa); bis(p-chlorophenyl)-4-biphenylylamine (IIb); N-phenyl-N-(4-biphenylyl)-p-toluidine (IIc); N-(4-biphenylyl)-N-(p-chlorophenyl)-p-toluidine (IId); N-phenyl-N-(4-biphenylyl)-p-anisidine (IIe); bis(m-anisyl)-4-biphenylylamine (IIIa); bis(m-tolyl)-4biphenylylamine (IIb); bis(m-chlorophenyl)-4-biphenylylamine (IIIc); N-phenyl-N-(4-biphenylyl)-m-toluidine (IIId); N-phenyl-N-(4-bromo-4'-biphenylyl)-m-toluidine (IVa); diphenyl-4-methyl-4'-biphenylylamine (IVb); N-phenyl-N-(4-ethoxycarbonyl-4'-biphenylyl)-m-toluidine (IVc); N-phenyl-N-(4-methoxy-4'-biphenylyl)-m-toluidine (IVd); N-(m-anisyl)-N-(4-biphenylyl)-p-toluidine (IVe); bis(m-anisyl)-3-biphenylylamine (Va); N-phenyl-N-(4-methyl-3'-biphenylyl)-p-toluidine (Vb); N-phenyl-N-(4-methyl-3'-biphenylyl)-m-anisidine (Vc); bis(m-anisyl)-3-biphenylylamine (Vd); bis(p-tolyl)-4-methyl-3'-biphenylylamine (Ve); N-p-tolyl-N-(4-methoxy-3'-biphenylyl)-m-chloroaniline (Vf), and the like.
It is also indicated in the aforementioned two copending applications that there may be selected as resin binders for the charge transport molecule components as illustrated in U.S. Pat. No. 3,121,006, the disclosure of which is totally incorporated herein by reference including polycarbonates, polyesters, epoxy resins, and the like. The aforementioned binders may also be selected as resin binders for the charge transport, and in some embodiments the photogenerating layers of the present invention.
While the abovementioned layered imaging members are suitable for their intended purposes, there continues to be a need for improved imaging members, particularly layered members, wherein the adhesive layer can be eliminated. Another need resides in the provision of layered imaging members wherein polyphosphazenes, including inorganic (phosphorous substituents such as inorganic metals, like copper) and polyorganophosphazenes can be selected as both the hole blocking layer and the adhesive layer. Further, there continues to be a need for layered imaging members wherein the layers are sufficiently adhered to one another to allow the continuous use of such members in repetitive imaging and printing systems. Also, there continues to be a need for improved seamless layered imaging members. Furthermore, there is a need for layered imaging members with the other advantages illustrated herein.